file-drawer effect

The file-drawer effect refers to the practice of
researchers filing away studies with negative outcomes. Negative outcome
refers to finding nothing of statistical significance or causal consequence,
not to finding that something affects us negatively. Negative outcome may
also refer to finding something that is contrary to one's earlier research
or to what one expects.

The practice of
reporting and publishing only positive-outcome
research creates a misrepresentation of the subject under investigation,
especially if a meta-analysis is done.

One criticism of parapsychology has been that its researchers have ignored
studies with negative outcomes. In 1975, the American Parapsychological
Association established an official policy against the selective reporting
of only positive results.

Little research seems to have done on the extent of the practice of
scientific researchers to file away studies with negative outcomes. Brian
Martinson, an investigator with the
HealthPartners Research
Foundation, led a study for the scientific journal Nature
(published in June 2005). Martinson and his colleagues sent a survey to
thousands of scientists funded by the National
Institutes of Health (which commissioned the study) and received 1,768 responses
with usable data from the 3,600 surveys mailed to mid-career scientists.
They received 1,479 responses with usable data from 4,160 surveys sent to
early-career scientists (Martinson
et al. 2005). The respondents were
allowed to remain anonymous. Of the scientists who
responded, 6.0 percent admitted to having "tossed out data because the information
contradicted their previous research." And more than 15 percent admitted
they had ignored observations because they had a "gut feeling" they were
inaccurate.*
Martinson et al. write:

our approach certainly leaves room for potential non-response bias;
misbehaving scientists may have been less likely than others to respond to
our survey, perhaps for fear of discovery and potential sanction. This,
combined with the fact that there is probably some under-reporting of
misbehaviours among respondents, would suggest that our estimates of
misbehaviour are conservative.

The drugs don't work: a modern medical scandal by Dr. Ben Goldacre "Seven trials had been conducted comparing reboxetine against a placebo. Only one, conducted in 254 patients, had a neat, positive result, and that one was published in an academic journal, for doctors and researchers to read. But six more trials were conducted, in almost 10 times as many patients. All of them showed that reboxetine was no better than a dummy sugar pill. None of these trials was published."--Ben Goldacre [The Guardian article is an excerpt from Bad Pharma: How Drug Companies Mislead Doctors and Harm Patientspublished in the UK September 25, 2012; to bepublished in the U.S. January 8, 2013.]